It’s not uncommon to hear or see that the Southern Expressway is backed up due to a crash during peak-hour periods. A couple of weeks ago, a truck and car collided at the Reynella exit, causing lengthy delays for commuters. On another occasion, dashcam footage exposed a motorbike rider doing dangerous stunts while overtaking other vehicles.

To help you get to your destination safely, RAA Senior Manager of Safety and Infrastructure Charles Mountain has a few tips for drivers on the Southern Expressway and other multi-lane highways.

1. Keep left

Unless you’re overtaking, you should be in the left or centre lanes as you drive along the Southern Expressway – it’s as simple as that.

Driving in the far-right lane from Darlington to Noarlunga could be a costly move. Other cars will need to pass you on the left, which generally isn’t illegal but can create dangerous situations. You might even receive a $281 fine, a $92 Victims of Crime Levy and two demerit points.

The same applies if you’re in a slower vehicle. Stay out of the right lane so you don’t get in the way of faster-moving traffic.

2. Leave some space

Driving only a couple of metres behind a slower vehicle as you drive up the Southern Expressway will not only annoy the person in front of you, but it might also cause a crash.

You need to adjust your speed accordingly if you’re getting too close or wait until there’s a safe space to overtake.

Mr Mountain says motorists need to remember the three-second rule.

“At 100km/h, you should be leaving a three second gap, which equates to about 80 metres behind the car in front,” Mr Mountain says.

3. Plan ahead

There’s nothing worse than being in the wrong lane and realising last minute that you need to exit the highway.

You then need to cut across two lanes of traffic to exit in time. This is an extremely dangerous manoeuvre that could cause a crash.

Instead, plan and make sure you’re in the left-hand lane well before reaching your exit.

While most navigation aids will steer you in the right direction, The Department for Infrastructure and Transport has a handy tool on their website.

4. Check your speed

Check the fixed and illuminated signs before you put your foot down to reach the 100km/h speed limit.

“The speed limit is often reduced when there’s been a crash, breakdown or there’s congestion and queued traffic ahead,” said Mr Mountain.

“Through the new Darlington section, and on the downhill section, between O’Halloran Hill and Darlington, the speed is 80km/h.

If necessary, change to a lower gear to help reduce and maintain your speed down the hill without constantly braking.”

A safety ramp is provided on the shoulder just before Marion Rd, which is designed to be used in an emergency situation when a vehicle loses braking capacity on the descent.

Motorists also need to watch their exit speed on the off ramps. Always check the posted and advised speed limit and slow down accordingly.

5. Entering the Southern Expressway

A recent samotor quiz  revealed that South Australians need to improve their merging knowledge. Almost half didn’t know the difference between a lane change and zip merge.

“If you’re entering the Southern Expressway from an on ramp, you’re required to give way to traffic already on the highway and wait for a suitable gap before merging,” Mr Mountain says.

“If you’re already on the expressway and approaching an on ramp, watch for entering traffic.”